I usually try a few new cosmos cultivars each year, but many of them never get planted. This annual does best when planted in the ground rather than started ahead of time, but with so many rabbits in my neighborhood looking for tender shoots to munch on, that’s not an option for me.
Cosmos started indoors (especially if they are a tall cultivar) will usually start to flop. And then there’s a good risk they’ll be beheaded when I’m sliding trays in and out to water the seedlings. Eventually I get frustrated by all the flopping and I toss them out.
One series that always behaves for me is Sonata, and last year I tried a new color called ‘Purple Shades’:
The plants stood up straight and behaved in their little planting packs, and I got a 100% germination rate.
The plants are bushy and grow 24 inches tall with what I would call royal purple blooms. The plants prefer full sun but will also grow in part-sun conditions, and they are not bothered by pests or diseases.